Metal air batteries are typically based on highly reactive substances and may have problems with corrosion during storage. For example, aluminum air batteries may be typically kept sitting without electrolyte because the electrolyte may corrode the aluminum during inactive periods. Emergency light aluminum air batteries, for example, may keep the electrolyte in a separate tank and release the electrolyte into the battery when operation is needed. Automotive aluminum air batteries may have complex systems to pump and time electrolyte introduction into the battery. Lithium batteries may have similar problems with aqueous electrolytes and thus may use polymer-type electrolytes.